Polysulfide sealant and preparation method thereof

Abstract

The invention relates to the technical field of sealing materials, in particular to a polysulfide sealant and a preparation method thereof. The polysulfide sealant comprises a first component and a second component, the first component comprises a combination of sulfydryl-terminated liquid polysulfide rubber and carbon black; the second component comprises a vulcanizing agent. The polysulfide sealant provided by the invention is low in weight loss and small in flexibility change in application, and has excellent medium resistance and sealing function.

Description

Technical Field

[0001] The present application relates to the technical field of sealing materials, and in particular to a polysulfide sealant and a preparation method thereof. Background Art

[0002] Polysulfide sealants are one of the most widely used non-metallic materials on aircraft because of their good tolerance to air, jet fuel, water vapor and atmospheric environment, and their wide working range. In order to ensure the excellent aging resistance and mechanical properties of the sealant, polysulfide rubber with a large number average molecular weight is generally selected as the base material. However, the large molecular weight of polysulfide rubber will cause the viscosity of the sealant to increase, which cannot meet the requirements of on-site process use. Generally, the viscosity is reduced by adding solvents or reducing the amount of fillers. The negative impact brought about by this is that the solvent content in the sealant increases, resulting in the solvent or other small molecular components being dissolved during the application of the sealant under conditions such as fuel immersion, causing serious weight loss of the sealant, thereby causing seal failure.

[0003] Therefore, it is crucial to develop a polysulfide sealant that can overcome the above-mentioned defects. Summary of the invention

[0004] In view of the above problems, the present application provides a polysulfide sealant and a preparation method thereof. The polysulfide sealant has low weight loss and small flexibility change during application, and has excellent media resistance and sealing function.

[0005] In a first aspect, the present application provides a polysulfide sealant, the polysulfide sealant comprising a first component and a second component;

[0006] The first component includes a combination of mercapto-terminated liquid polysulfide rubber and carbon black;

[0007] The second component includes a vulcanizing agent.

[0008] In the technical solution of the implementation mode of the present application, the mid-terminal mercapto liquid polysulfide rubber and carbon black in the first component are used in combination, and the viscosity of the formed first component is stable. The polysulfide sealant further formed has stable performance during process use, and can achieve low weight loss and small flexibility change during application. Therefore, the polysulfide sealant has excellent media resistance and sealing function.

[0009] In some embodiments, the mass ratio of the first component to the second component is 100:(8-12).

[0010] In some embodiments, the number average molecular weight of the mercapto-terminated liquid polysulfide rubber is ≤10000 g / mol.

[0011] In some embodiments, the weight content of the mercapto groups in the mercapto-terminated liquid polysulfide rubber is 1%-5%.

[0012] In some embodiments, the mercapto-terminated liquid polysulfide rubber is obtained by internal exchange reaction of at least two mercapto-terminated liquid polysulfide rubber raw materials with number average molecular weights.

[0013] In the technical scheme of the implementation mode of the present application, at least two number-average molecular weight terminated mercapto liquid polysulfide rubber raw materials are subjected to internal exchange reaction to obtain mercapto terminated liquid polysulfide rubbers of different viscosities as needed, thereby increasing the content of carbon black in the first component, further improving the media resistance and sealing function of the polysulfide sealant.

[0014] In some embodiments, the mercapto-terminated liquid polysulfide rubber is obtained by an internal exchange reaction between a first mercapto-terminated liquid polysulfide rubber and a second mercapto-terminated liquid polysulfide rubber;

[0015] The number average molecular weight of the first terminal mercapto liquid polysulfide rubber is 1000-3000 g / mol;

[0016] The number average molecular weight of the second terminal mercapto liquid polysulfide rubber is 5000-6000 g / mol; and / or;

[0017] The mass ratio of the first mercapto-terminated liquid polysulfide rubber to the second mercapto-terminated liquid polysulfide rubber is (30-80):(20-70).

[0018] In some embodiments, the structural formula of the mercapto-terminated liquid polysulfide rubber is as shown in Formula I:

[0019]

[0020] wherein a, b and c are each independently selected from an integer of 1-200; x and y are each independently selected from an integer of 0-10; preferably x and y are both 0;

[0021] R 1 , R 2 , R 3 Each independently selected from C3-C20 first alkyleneoxy and second alkyleneoxy alkylene; further preferably -C 2 H 4 -O-CH 2 -OC 2 H 4 -;

[0022] R 4 is H, substituted or unsubstituted C1-C10 alkyl;

[0023] The substituent is selected from halogen, hydroxyl, mercapto, and C1-C6 alkyl.

[0024] In some embodiments, the structural formulas of the mercapto-terminated liquid polysulfide rubber raw material, the first mercapto-terminated liquid polysulfide rubber, and the second mercapto-terminated liquid polysulfide rubber are independently as shown in Formula I.

[0025] In some embodiments, the carbon black includes semi-reinforcing furnace black.

[0026] In the technical solution of the embodiment of the present application, the carbon black is preferably semi-reinforced furnace black, which has the characteristics of low solvent extract content and good process performance of the rubber compared with other carbon blacks, thereby improving the media resistance and sealing function of the polysulfide sealant.

[0027] In some embodiments, the true density of the carbon black is 1 to 3 g / cm 3 .

[0028] In some embodiments, the average particle size of the carbon black is 60 to 130 nm.

[0029] In some embodiments, the carbon black has an oil absorption value of 0.45 to 0.8 mL / g.

[0030] In some embodiments, based on 100% of the total mass of the mercapto-terminated liquid polysulfide rubber, the mass of the carbon black is 5%-30%.

[0031] In the technical solution of the implementation mode of the present application, when the carbon black is added in a relatively high amount, the basic properties of the terminal mercapto liquid polysulfide rubber are less affected, and low weight loss and small change in flexibility of the polysulfide sealant can be achieved during application.

[0032] In some embodiments, the first component further comprises an auxiliary agent.

[0033] In some embodiments, the auxiliary agent includes any one of a reinforcing filler, a first plasticizer, or a coupling agent, or a combination of at least two thereof.

[0034] In some embodiments, the reinforcing filler includes any one of silicon dioxide, calcium carbonate, or titanium dioxide, or a combination of at least two thereof.

[0035] In some embodiments, based on the total mass of the mercapto-terminated liquid polysulfide rubber being 100%, the mass of the reinforcing filler is 10%-50%.

[0036] In some embodiments, the first plasticizer includes any one of phthalates, chlorinated paraffin, or tributyl phosphate, or a combination of at least two thereof.

[0037] In some embodiments, based on 100% of the total mass of the mercapto-terminated liquid polysulfide rubber, the mass of the first plasticizer is 1%-5%.

[0038] In some embodiments, the coupling agent includes a resin coupling agent and / or a silane coupling agent.

[0039] In some embodiments, based on the total mass of the mercapto-terminated liquid polysulfide rubber being 100%, the mass of the coupling agent is 1%-5%.

[0040] In some embodiments, the sulfiding agent includes manganese dioxide.

[0041] In some embodiments, the vulcanizing agent further includes a vulcanization aid.

[0042] In some embodiments, the vulcanization aid includes any one or a combination of at least two of a second plasticizer, an accelerator, or a vulcanization inhibitor.

[0043] In some embodiments, the second plasticizer includes any one of an ester plasticizer, hydrogenated terphenyl, or chlorinated paraffin, or a combination of at least two thereof.

[0044] In some embodiments, based on 100% of the total mass of the manganese dioxide, the mass of the second plasticizer is 60%-120%.

[0045] In some embodiments, the accelerator includes any one of diphenylguanidine, tetramethylthiuram disulfide, or zinc dibutyldithiocarbamate, or a combination of at least two thereof.

[0046] In some embodiments, based on 100% of the total mass of the manganese dioxide, the mass of the promoter is 1%-10%.

[0047] In some embodiments, the vulcanization inhibitor includes stearic acid and / or oleic acid.

[0048] In some embodiments, based on 100% of the total mass of the manganese dioxide, the mass of the sulfidation inhibitor is 0.5%-10%.

[0049] In a second aspect, the present application provides a method for preparing a polysulfide sealant, the preparation method comprising the following steps:

[0050] The mercapto-terminated liquid polysulfide rubber and carbon black are mixed for the first time to obtain a first component.

[0051] In some embodiments, manganese dioxide and the vulcanization aid are mixed a second time to obtain a second component.

[0052] In some embodiments, before the first mixing, the method further comprises subjecting the mercapto-terminated liquid polysulfide rubber raw materials with different number average molecular weights to an internal exchange reaction.

[0053] In some embodiments, the internal exchange reaction comprises stirring and mixing.

[0054] In some embodiments, the temperature of the stirring and mixing is 60-80°C.

[0055] In some embodiments, the stirring and mixing time is 1-6 hours.

[0056] In some embodiments, the stirring and mixing is performed under vacuum conditions.

[0057] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. DETAILED DESCRIPTION

[0058] The following is a detailed description of the embodiments of the technical solution of the present application. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the specification, claims and description of this application and any variations thereof are intended to cover non-exclusive inclusions.

[0060] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0061] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0062] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following ranges can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents an abbreviation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "2-10" means that all real numbers between "2-10" are listed in this document, and "2-10" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0063] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0064] In the prior art, during the application of polysulfide sealants, under conditions such as fuel immersion, solvents or other small molecular components are dissolved, resulting in large weight loss and flexibility changes, causing the polysulfide sealants to fail.

[0065] In the present application, the polysulfide sealant formed by combining the mercapto-terminated liquid polysulfide rubber and carbon black can achieve low weight loss and small change in flexibility during application, thereby improving the media resistance and sealing function of the polysulfide sealant. The present application provides a polysulfide sealant and a preparation method thereof.

[0066] [Polysulfide sealant]

[0067] In some embodiments, the present application provides a polysulfide sealant, the polysulfide sealant comprising a first component and a second component;

[0068] The first component includes a combination of mercapto-terminated liquid polysulfide rubber and carbon black;

[0069] The second component includes a vulcanizing agent.

[0070] In the prior art, there is no effective method for improving the weight loss and flexibility change of polysulfide sealants during application.

[0071] In the technical solution of the embodiment of the present application, the mid-terminal mercapto liquid polysulfide rubber and carbon black in the first component are used in combination, and the viscosity of the first component formed is stable. The polysulfide sealant further formed has stable performance during process use, and can achieve low weight loss and small flexibility change during application. Therefore, the polysulfide sealant has excellent media resistance and sealing function.

[0072] In some embodiments, the mass ratio of the first component to the second component is 100:(8-12), wherein 8-12 can be 9, 10, 11, etc.

[0073] In some embodiments, the number average molecular weight of the mercapto-terminated liquid polysulfide rubber is ≤10000 g / mol, for example, 1000 g / mol, 2000 g / mol, 4000 g / mol, 6000 g / mol, 8000 g / mol, etc.

[0074] In the present application, the test method for the number average molecular weight of the mercapto-terminated liquid polysulfide rubber is gel chromatography permeation method (GPC method), specifically:

[0075] (1) Accurately weigh the polymer sample to be tested and dissolve it in an appropriate solvent to ensure that the sample is completely dissolved; then filter the sample solution using a 0.2 μm or 0.45 μm filter membrane to remove any particulate matter and control the sample concentration to be within the range of 2-5 mg / mL.

[0076] (2) Select a suitable mobile phase, which is usually a solvent that can dissolve the polymer, such as tetrahydrofuran (THF), dichloromethane, chloroform or others. Then filter the mobile phase through a 0.45 μm filter membrane and degas to remove bubbles.

[0077] (3) Test and chromatogram analysis are performed in a GPC system to calculate the number average molecular weight.

[0078] In some embodiments, the weight content of the mercapto groups in the mercapto-terminated liquid polysulfide rubber is 1%-5%, such as 2%, 3%, 4%, etc.

[0079] In the present application, the mercapto-terminated liquid polysulfide rubber can be purchased commercially or can be homemade.

[0080] In some embodiments, the mercapto-terminated liquid polysulfide rubber is obtained by internal exchange reaction of at least two mercapto-terminated liquid polysulfide rubber raw materials with number average molecular weights.

[0081] In the technical solution of the embodiment of the present application, at least two number-average molecular weight terminated mercapto liquid polysulfide rubber raw materials are subjected to internal exchange reaction to obtain mercapto terminated liquid polysulfide rubbers of different viscosities as needed, thereby increasing the content of carbon black in the first component, further improving the media resistance and sealing function of the polysulfide sealant.

[0082] In the present application, the structural formula of the mercapto-terminated liquid polysulfide rubber raw material may also be as shown in Formula I below, and may be commercially available or homemade.

[0083] In some embodiments, the mercapto-terminated liquid polysulfide rubber is obtained by an internal exchange reaction between a first mercapto-terminated liquid polysulfide rubber and a second mercapto-terminated liquid polysulfide rubber;

[0084] The number average molecular weight of the first end mercapto liquid polysulfide rubber is 1000-3000 g / mol, such as 1500 g / mol, 2000 g / mol, 2500 g / mol, etc.;

[0085] The number average molecular weight of the second terminal mercapto liquid polysulfide rubber is 5000-6000 g / mol, such as 5200 g / mol, 5400 g / mol, 5600 g / mol, 5800 g / mol, etc.; and / or;

[0086] The mass ratio of the first terminal mercapto liquid polysulfide rubber to the second terminal mercapto liquid polysulfide rubber is (30-80):(20-70), wherein 30-80 may be 40, 50, 60, 70, etc., and 20-70 may be 30, 40, 50, 60, etc.

[0087] In the present application, the structural formula of the first mercapto-terminated liquid polysulfide rubber and the second mercapto-terminated liquid polysulfide rubber may also be as shown in Formula I below, and may be commercially available or homemade.

[0088] In some embodiments, the structure of the mercapto-terminated liquid polysulfide rubber is as shown in Formula I:

[0089]

[0090] wherein a, b and c are each independently selected from an integer of 1-200 (e.g., 10, 20, 40, 60, 80, 100, 120, 140, 160, 180, etc.); x and y are each independently selected from an integer of 0-10 (e.g., 2, 4, 6, 8, etc.); preferably, x and y are both 0;

[0091] R 1 , R 2 , R 3Each independently selected from C3 to C20 (e.g., C4, C6, C8, C10, C12, C14, C16, C18, etc.) a first alkyleneoxy group and a second alkyleneoxy group; more preferably -C 2 H 4 -O-CH 2 -OC 2 H 4 -;

[0092] R 4 is H, substituted or unsubstituted C1-C10 (e.g., C2, C4, C6, C8, etc.) alkyl;

[0093] The substituent is selected from halogen, hydroxyl, mercapto, C1-C6 alkyl (eg, C2, C3, C4, C5, etc.).

[0094] In the present application, C3-C20 means that the number of carbon atoms in the main chain is 3-20, and other similar expressions are the same.

[0095] When the aforementioned alkylene group contains an oxygen atom, it may be an alkyleneoxy group, and the first alkyleneoxy group and the second alkyleneoxyalkylene group are represented by -ROR′OR″-, wherein R, R′ and R″ refer to the alkylene group described in the present application.

[0096] In the present application, the structure of the mercapto-terminated liquid polysulfide rubber has a cross-linked structure. The mercapto-terminated liquid polysulfide rubber can be purchased commercially or made in-house. When made in-house, a cross-linking agent is required to participate in the reaction. The type of the cross-linking agent can be selected from known materials, and the amount added can be adaptively adjusted according to the number average molecular weight of the mercapto-terminated liquid polysulfide rubber.

[0097] In some embodiments, the structural formulas of the mercapto-terminated liquid polysulfide rubber raw material, the first mercapto-terminated liquid polysulfide rubber, and the second mercapto-terminated liquid polysulfide rubber are independently as shown in Formula I.

[0098] In some embodiments, the carbon black comprises semi-reinforcing furnace black.

[0099] In the technical solution of the embodiment of the present application, the carbon black is preferably semi-reinforced furnace black, which has the characteristics of low solvent extract content and good process performance of the rubber compared with other carbon blacks, thereby improving the media resistance and sealing function of the polysulfide sealant.

[0100] In some embodiments, the true density of the carbon black is 1 to 3 g / cm 3 , for example 1.2 g / cm 3 , 1.4g / cm 3 , 1.6g / cm 3 , 1.8g / cm 3 , 2g / cm 3 , 2.2g / cm3 , 2.4g / cm 3 , 2.6g / cm 3 , 2.8g / cm 3 wait.

[0101] In this application, the true density refers to the actual mass of a solid substance per unit volume in an absolutely dense state, that is, the density excluding internal pores or inter-particle spaces. The test method is the gas volume method (helium displacement method), which specifically uses the Boyle's law (PV=nRT) of an inert gas with a small molecular diameter (such as helium) under certain conditions to accurately measure the true volume of the sample by measuring the change in gas volume caused by placing the sample in the sample test chamber, and then obtains the true density according to the calculation method of true density=mass / true volume.

[0102] In some embodiments, the average particle size of the carbon black is 60 to 130 nm, for example, 80 nm, 90 nm, 100 nm, 110 nm, 120 nm, etc.

[0103] In the present application, the average particle size refers to the volume average diameter, and the testing method is the laser diffraction method, using a laser diffraction particle size analyzer for testing.

[0104] In some embodiments, the oil absorption value of the carbon black is 0.45-0.8 mL / g, for example, 0.5 mL / g, 0.6 mL / g, 0.7 mL / g, etc.

[0105] In the present application, the oil absorption value is an important indicator to measure the adsorption capacity of powder materials for oil substances, and is expressed as the volume of linseed oil or dioctyl ester (DOP) required for 1 gram of powder, and the unit is mL / g.

[0106] In some embodiments, based on the total mass of the mercapto-terminated liquid polysulfide rubber being 100%, the mass of the carbon black is 5%-30%, for example, 10%, 15%, 20%, 25%, etc.

[0107] In the technical solution of the embodiment of the present application, when the carbon black is added in a relatively high amount, the basic properties of the terminal mercapto liquid polysulfide rubber are less affected, and low weight loss and small change in flexibility of the polysulfide sealant can be achieved during application.

[0108] In some embodiments, the first component further includes an adjuvant.

[0109] In some embodiments, the auxiliary agent includes any one of a reinforcing filler, a first plasticizer, or a coupling agent, or a combination of at least two thereof.

[0110] In some embodiments, the reinforcing filler includes any one of silicon dioxide, calcium carbonate, or titanium dioxide, or a combination of at least two thereof.

[0111] In some embodiments, based on the total mass of the terminated mercapto liquid polysulfide rubber as 100%, the mass of the reinforcing filler is 10%-50%, for example, 15%, 20%, 5%, 30%, 35%, 40%, 45%, etc.

[0112] In some embodiments, the first plasticizer includes any one of phthalates, chlorinated paraffin, or tributyl phosphate, or a combination of at least two thereof.

[0113] In some embodiments, based on the total mass of the mercapto-terminated liquid polysulfide rubber being 100%, the mass of the first plasticizer is 1%-5%, for example, 2%, 3%, 4%, etc.

[0114] In some embodiments, the coupling agent includes a resin coupling agent and / or a silane coupling agent.

[0115] In some embodiments, based on the total mass of the mercapto-terminated liquid polysulfide rubber being 100%, the mass of the coupling agent is 1%-5%, for example, 2%, 3%, 4%, etc.

[0116] In some embodiments, the sulfiding agent includes manganese dioxide.

[0117] In some embodiments, the vulcanizing agent further includes a vulcanization aid.

[0118] In some embodiments, the vulcanization aid includes any one or a combination of at least two of a second plasticizer, an accelerator, or a vulcanization inhibitor.

[0119] In some embodiments, the second plasticizer includes any one of ester plasticizers, hydrogenated terphenyl, or chlorinated paraffin, or a combination of at least two thereof.

[0120] In some embodiments, based on the total mass of the manganese dioxide being 100%, the mass of the second plasticizer is 60%-120%, for example, 70%, 80%, 90%, 100%, 110%, etc.

[0121] In some embodiments, the accelerator includes any one of diphenylguanidine, tetramethylthiuram disulfide, or zinc dibutyldithiocarbamate, or a combination of at least two thereof.

[0122] In some embodiments, based on the total mass of the manganese dioxide being 100%, the mass of the promoter is 1%-10%, for example, 2%, 4%, 6%, 8%, etc.

[0123] In some embodiments, the vulcanization inhibitor includes stearic acid and / or oleic acid.

[0124] In some embodiments, based on the total mass of the manganese dioxide being 100%, the mass of the sulfidation inhibitor is 0.5%-10%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, etc.

[0125] In some embodiments, the polysulfide sealant includes a first component and a second component in a mass ratio of 100:(8-12);

[0126] The first component, based on the total mass of the mercapto-terminated liquid polysulfide rubber as 100%, includes the following components:

[0127] 100% thiol-terminated liquid polysulfide rubber, 5%-30% semi-reinforcing furnace black, 10%-50% reinforcing filler, 1%-5% first plasticizer and 1%-5% coupling agent;

[0128] The second component, based on the total mass of manganese dioxide as 100%, comprises the following components:

[0129] 100% manganese dioxide, 60%-120% second plasticizer, 1%-10% accelerator and 0.5%-10% vulcanization inhibitor.

[0130] [Preparation method of polysulfide sealant]

[0131] In some embodiments, the present application provides a method for preparing the polysulfide sealant, the method comprising the following steps:

[0132] The mercapto-terminated liquid polysulfide rubber and carbon black are mixed for the first time to obtain a first component.

[0133] In some embodiments, manganese dioxide and the vulcanization aid are mixed a second time to obtain a second component.

[0134] In some embodiments, before the first mixing, the step further includes subjecting the mercapto-terminated liquid polysulfide rubber raw materials with different number average molecular weights to an internal exchange reaction.

[0135] In some embodiments, the internal exchange reaction comprises stirring and mixing.

[0136] In some embodiments, the stirring and mixing temperature is 60-80°C, for example, 62°C, 64°C, 66°C, 68°C, 70°C, 72°C, 74°C, 76°C, 78°C, etc.

[0137] In some embodiments, the stirring and mixing time is 1-6 hours, such as 2 hours, 3 hours, 4 hours, 5 hours, etc.

[0138] In some embodiments, the stirring and mixing is performed under vacuum conditions; optionally, the vacuum degree is ≤-0.08MPa.

[0139] In some embodiments, the first mixing and the second mixing include grinding; for example, grinding is performed using a three-roller grinder; as an example, the number of grinding times is 3 to 5 times.

[0140] In some embodiments, the method for preparing the polysulfide sealant comprises the following steps:

[0141] (1) Stirring and mixing terminal mercapto liquid polysulfide rubber raw materials of different number average molecular weights at 60-80° C. and vacuum degree ≤-0.08 MPa for 1-6 hours to carry out internal exchange reaction; then adding reinforcing filler, first plasticizer and coupling agent according to the formula amount, grinding in a three-roll mill for 3-5 times to obtain a first component;

[0142] (2) Grind manganese dioxide, a second plasticizer, an accelerator and a vulcanization inhibitor in a three-roll mill for 3 to 5 times according to the formula amount to obtain a second component.

[0143] [Example]

[0144] Example 1

[0145] Polysulfide sealant:

[0146] (1) First component: First, put the terminated mercapto liquid polysulfide rubber of different molecular weights into a double planetary mixer according to the formula amount, stir for 3 hours at a temperature of 70°C and a vacuum degree of less than -0.08MPa to carry out an internal exchange reaction; then add the remaining components according to the formula amount, grind them four times with a three-roll grinder to form a uniform mixture as a base paste, i.e., the first component.

[0147] (2) Second component: Manganese dioxide, plasticizer, accelerator and vulcanization inhibitor are roughly mixed in advance according to the formula amount, and then ground five times with a three-roll mill to form a uniform mixture as a vulcanizing agent, i.e., the second component.

[0148] In Example 1, the mass ratio of the first component to the second component is 100:10, and the formula of the first component and the second component is shown in Table 1:

[0149] Table 1

[0150]

[0151]

[0152] Example 2

[0153] The polyether vulcanizing agent was obtained according to the method described in Example 1, wherein the mass ratio of the first component to the second component was 100:12, and the formula of the first component and the second component was shown in Table 2:

[0154] Table 2

[0155]

[0156] Example 3

[0157] A polyether vulcanizing agent was obtained according to the method described in Example 1, wherein the mass ratio of the first component to the second component was 100:8, and the formula of the first component and the second component was shown in Table 3:

[0158] Table 3

[0159]

[0160] Example 4

[0161] The polyether vulcanizing agent was obtained according to the method described in Example 1, wherein the mass ratio of the first component to the second component was 100:10, and the formula of the first component and the second component was shown in Table 4:

[0162] Table 4

[0163]

[0164]

[0165] Example 5

[0166] The polyether vulcanizing agent was obtained according to the method described in Example 1, wherein the mass ratio of the first component to the second component was 100:10, and the formula of the first component and the second component was shown in Table 5:

[0167] Table 5

[0168]

[0169] In the above examples, the specific information and sources of each raw material are as follows:

[0170] Mercapto-terminated liquid polysulfide rubber:

[0171] Among them, R 1 , R 2 and R 3 For -C 2 H 4 -O-CH 2 -OC 2 H 4 -, R 4 is hydrogen, x and y are 1, a, b and c are adjusted to have a number average molecular weight as shown in the table, and the mercapto-terminated liquid polysulfide rubber was purchased from Jinxi Chemical Research Institute.

[0172] Example 6

[0173] The difference between this embodiment and embodiment 1 is that the semi-reinforcing furnace black is replaced with white carbon black, and the rest is the same as embodiment 1.

[0174] Example 7

[0175] The difference between this embodiment and embodiment 1 is that two number average molecular weight terminated mercapto liquid polysulfide rubbers and other components are directly ground with a three-roll mill without internal exchange reaction. The rest is the same as embodiment 1.

[0176] Example 8

[0177] The difference between this embodiment and embodiment 1 is that the two number average molecular weight terminal mercapto liquid polysulfide rubbers are replaced by linear terminal mercapto liquid polysulfide rubbers, that is, the basic structure is The number average molecular weights of a and b are adjusted as shown in the table. The mercapto-terminated liquid polysulfide rubber was purchased from Jinxi Chemical Research Institute. The rest are the same as in Example 1.

[0178] Comparative Example 1

[0179] The difference between this comparative example and Example 1 is that semi-reinforcing furnace black is not included, and the rest is the same as Example 1.

[0180] [Performance test]

[0181] 1. The first component:

[0182] (1) Viscosity: The test is carried out in accordance with the standard of AS5127 / 1 (5.3). Specifically, the base paste to be tested is placed in a can-shaped container with a volume of not less than 473 ml, with the liquid level of the base paste not more than 12.7 mm from the top of the can, and is placed in a sealed container at 25°C for at least 8 hours; after being slowly stirred with a stirring rod for at least 3 minutes, the container is placed in a sealed container at 25°C for 1 hour to 2 hours; the viscosity is measured at 25°C, and the highest value of the viscometer reading is taken when the viscometer is running for 60 seconds to 70 seconds, with an accuracy of 1 Pa·s.

[0183] 2. Polysulfide sealant:

[0184] The first component and the second component of the polysulfide sealant were mixed according to the mass ratio and cured at room temperature for 14 days; the cured sample was tested as follows:

[0185] (1) Weight loss: The test is carried out in accordance with AS5127 / 1 (7.4). Specifically, the weight of three test pieces in air (W1) is measured to an accuracy of 0.001 g. The test pieces are immersed in a glass jar containing at least 900 ml of AMS2629 Type 1 reference solution, sealed and placed in a forced air drying oven for 7 days at 60°C. The test pieces are taken out and immediately dipped in methanol. The test pieces are then dried at 49°C for 24 hours and cooled to room temperature in a desiccator under standard conditions. The three test pieces (W2) are then weighed to an accuracy of 0.001 g. The weight loss of the sealant is calculated to an accuracy of 0.1% according to the following formula.

[0186] Weight loss = (W1-W2) / W1×100%

[0187] (2) Flexibility test: The test was conducted in accordance with the standard of AS5127 / 1 (7.4). Specifically, the sample after the weight loss test was bent 180° on a mandrel with a diameter of Φ3.18 mm, and its surface morphology was observed.

[0188] (3) Tensile strength and elongation at break: The test was conducted in accordance with the standard AS5127 / 1 (7.7). Specifically, the thickness of the specimen was measured at three points within the distance between the test points using a thickness gauge according to ASTM D412, and the median value t was recorded. The two ends of the specimen were fixed with the clamps of the electronic tensile testing machine, and the distance between the test points of the specimen was set to (25.00±0.25) mm so that the specimen was centered. The separation speed of the two clamps of the electronic tensile testing machine was set to (508±25) mm / min. The electronic tensile testing machine was turned on until the specimen broke, and the force value at the time of breaking was recorded to an accuracy of 0.1 N. The elongation at break displayed by the machine was recorded to an accuracy of 1%.

[0189] The tensile strength is calculated as follows:

[0190] Ts=P / (t×6)×1000

[0191] P——Force value when the sample is pulled off, N;

[0192] t——specimen thickness, mm.

[0193] The test results are summarized in Table 6.

[0194] Table 6

[0195]

[0196]

[0197] Analysis of the data in Table 6 shows that the viscosity of the first component in the polysulfide sealant described in the present application is between 472-1633 Pa·s, the tensile strength of the polysulfide sealant is between 2.2-3.3 MPa, the elongation at break is between 319%-548%, the weight loss is within 6.7%, preferably within 4.2%, and the sample after weight loss testing is bent 180° on a mandrel with a diameter of Φ3.18 mm without cracks or gaps; the viscosity of the first component in the polysulfide sealant described in the present application is adjustable, and the polysulfide sealant has the characteristics of low weight loss and small flexibility change on the basis of excellent mechanical properties. Therefore, the polysulfide sealant has medium resistance and sealing function.

[0198] Analysis of Comparative Example 1 and Example 1 shows that the performance of Comparative Example 1 is not as good as that of Example 1, which proves that the first component in the polysulfide sealant described in the present application has better performance when combined with carbon black.

[0199] Analysis of Example 6 and Example 1 shows that the performance of Example 6 is not as good as that of Example 1, which proves that the polysulfide sealant formed by carbon black preferably semi-reinforced furnace black has better performance.

[0200] Analysis of Examples 7-8 and Example 1 shows that the performance of Examples 7-8 is not as good as that of Example 1, which proves that the polysulfide sealant formed by the mercapto-terminated liquid polysulfide rubber described in the present application has better performance.

[0201] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A polysulfide sealant, characterized in that: The polysulfide sealant comprises a first component and a second component; The first component includes a combination of mercapto-terminated liquid polysulfide rubber and carbon black; The second component includes a vulcanizing agent.

2. The polysulfide sealant according to claim 1, characterized in that The mass ratio of the first component to the second component is 100:(8-12).

3. The polysulfide sealant according to claim 1 or 2, characterized in that: The number average molecular weight of the mercapto-terminated liquid polysulfide rubber is ≤10000 g / mol; Preferably, the weight content of mercapto groups in the mercapto-terminated liquid polysulfide rubber is 1%-5%; Preferably, the mercapto-terminated liquid polysulfide rubber is obtained by internal exchange reaction of at least two mercapto-terminated liquid polysulfide rubber raw materials with number average molecular weights; Preferably, the mercapto-terminated liquid polysulfide rubber is obtained by an internal exchange reaction between a first mercapto-terminated liquid polysulfide rubber and a second mercapto-terminated liquid polysulfide rubber; The number average molecular weight of the first terminal mercapto liquid polysulfide rubber is 1000-3000 g / mol; The number average molecular weight of the second terminal mercapto liquid polysulfide rubber is 5000-6000 g / mol; and / or; The mass ratio of the first mercapto-terminated liquid polysulfide rubber to the second mercapto-terminated liquid polysulfide rubber is (30-80):(20-70).

4. The polysulfide sealant according to any one of claims 1 to 3, characterized in that: The structural formula of the mercapto-terminated liquid polysulfide rubber is shown in Formula I: wherein a, b and c are each independently selected from an integer of 1-200; x and y are each independently selected from an integer of 0-10; preferably x and y are both 0; R1, R2, and R3 are each independently selected from C3 to C20 first alkyleneoxy and second alkyleneoxy alkylene; further preferably -C2H4-O-CH2-O-C2H4-; R4 is H, substituted or unsubstituted C1-C10 alkyl; The substituent is selected from halogen, hydroxyl, mercapto, C1-C6 alkyl; Preferably, the structural formulas of the mercapto-terminated liquid polysulfide rubber raw material, the first mercapto-terminated liquid polysulfide rubber and the second mercapto-terminated liquid polysulfide rubber are independently as shown in Formula I.

5. The polysulfide sealant according to any one of claims 1 to 4, characterized in that: The carbon black includes semi-reinforced furnace black; Preferably, the true density of the carbon black is 1 to 3 g / cm 3 ; Preferably, the average particle size of the carbon black is 60 to 130 nm; Preferably, the oil absorption value of the carbon black is 0.45 to 0.8 mL / g; Preferably, based on 100% of the total mass of the mercapto-terminated liquid polysulfide rubber, the mass of the carbon black is 5%-30%.

6. The polysulfide sealant according to any one of claims 1 to 5, characterized in that: The first component also includes an auxiliary agent; Preferably, the auxiliary agent includes any one of a reinforcing filler, a first plasticizer or a coupling agent, or a combination of at least two of them.

7. The polysulfide sealant according to claim 6, characterized in that The reinforcing filler includes any one of silicon dioxide, calcium carbonate or titanium dioxide or a combination of at least two thereof; Preferably, based on the total mass of the mercapto-terminated liquid polysulfide rubber being 100%, the mass of the reinforcing filler is 10%-50%; Preferably, the first plasticizer includes any one or a combination of at least two of phthalic acid substances, chlorinated paraffin or tributyl phosphate; Preferably, based on the total mass of the mercapto-terminated liquid polysulfide rubber being 100%, the mass of the first plasticizer is 1%-5%; Preferably, the coupling agent includes a resin coupling agent and / or a silane coupling agent; Preferably, based on the total mass of the mercapto-terminated liquid polysulfide rubber being 100%, the mass of the coupling agent is 1%-5%.

8. The polysulfide sealant according to any one of claims 1 to 7, characterized in that: The sulfiding agent includes manganese dioxide; Preferably, the vulcanizing agent further comprises a vulcanizing aid; Preferably, the vulcanization aid comprises any one or a combination of at least two of a second plasticizer, an accelerator or a vulcanization inhibitor; Preferably, the second plasticizer includes any one or a combination of at least two of an ester plasticizer, hydrogenated terphenyl or chlorinated paraffin; Preferably, based on the total mass of the manganese dioxide being 100%, the mass of the second plasticizer is 60%-120%; Preferably, the accelerator comprises any one of diphenylguanidine, tetramethylthiuram disulfide or zinc dibutyldithiocarbamate or a combination of at least two thereof; Preferably, based on the total mass of the manganese dioxide being 100%, the mass of the promoter is 1%-10%; Preferably, the vulcanization inhibitor comprises stearic acid and / or oleic acid; Preferably, based on 100% of the total mass of the manganese dioxide, the mass of the sulfidation inhibitor is 0.5%-10%.

9. A method for preparing a polysulfide sealant, characterized in that: The preparation method comprises the following steps: Mixing the mercapto-terminated liquid polysulfide rubber and carbon black for the first time to obtain a first component; Preferably, manganese dioxide and the vulcanization aid are mixed for a second time to obtain a second component.

10. The preparation method according to claim 9, characterized in that: Before the first mixing, the step further includes subjecting the mercapto-terminated liquid polysulfide rubber raw materials with different number average molecular weights to an internal exchange reaction; Preferably, the internal exchange reaction comprises stirring and mixing; Preferably, the stirring and mixing temperature is 60-80°C; Preferably, the stirring and mixing time is 1-6h; Preferably, the stirring and mixing is performed under vacuum conditions.

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